/// <summary>
/// Applies the Bayesian Discriminant function at protein level
/// </summary>
/// <param name="myParams"></param>
public void BayesianCleaningAtProteinLevel()
{
int minNoExamplesPerClass = 5;
PatternTools.GaussianDiscriminant.Discriminant gd = new PatternTools.GaussianDiscriminant.Discriminant();
List <int> dims = new List <int> {
0, 1, 2, 3, 4, 5
};
int negativeClassExampleCounter = 0;
foreach (MyProtein p in MyProteinList)
{
//Find out what class does this belong
double label = 1;
if (p.Locus.StartsWith(myParams.LabeledDecoyTag))
{
label = -1;
negativeClassExampleCounter++;
}
gd.MySparseMatrix.addRow(new sparseMatrixRow((int)label, dims, p.InputVector));
}
//We need to make sure everything is working properly in this new normalization
//This greately degrades the classifier!!! never use!!!!
//gd.MySparseMatrix.NormalizeAllColumnsToRangeFrom0To1New();
//------
Console.WriteLine("Target examples for protein model = " + gd.MySparseMatrix.theMatrixInRows.FindAll(a => a.Lable == 1).Count);
Console.WriteLine("Decoy examples for protein model = " + gd.MySparseMatrix.theMatrixInRows.FindAll(a => a.Lable == -1).Count);
gd.Model(false, new List <int>(), minNoExamplesPerClass, true, false);
if (gd.ClassLableClassPackageDic.Keys.Count != 2)
{
throw new System.ArgumentException("Not enough examples to generate protein classification model. No available negative datapoints: " + negativeClassExampleCounter);
}
Parallel.ForEach(MyProteinList, r =>
//foreach (Scan s in p.MyScans)
{
//The result is ordered by class number
var results = gd.Classify(r.InputVector.ToArray());
double BayesianDiference = results[0].Score - results[1].Score;
r.BayesianScore = BayesianDiference;
}
);
double BayesianMin = MyProteinList.Min(a => a.BayesianScore);
double BayesianMax = MyProteinList.Max(a => a.BayesianScore);
double BayesianDif = BayesianMax - BayesianMin;
MyProteinList.Sort((a, b) => b.BayesianScore.CompareTo(a.BayesianScore));
int numberOfReverseProteins = MyProteinList.FindAll(a => a.Locus.StartsWith(myParams.LabeledDecoyTag)).Count;
int numberOfForwardProteins = MyProteinList.FindAll(a => !a.Locus.StartsWith(myParams.LabeledDecoyTag)).Count;
//Now lets do the filtering
int cutOffValue = MyProteinList.Count;
for (cutOffValue = MyProteinList.Count - 1; cutOffValue > 0; cutOffValue--)
{
if (MyProteinList[cutOffValue].Locus.StartsWith(myParams.LabeledDecoyTag))
{
numberOfReverseProteins--;
}
else
{
numberOfForwardProteins--;
}
//Calculate FDR;
double fdr = (double)numberOfReverseProteins / ((double)numberOfForwardProteins + (double)numberOfReverseProteins);
if (fdr <= myParams.ProteinFDR)
{
break;
}
}
MyProteinList.RemoveRange(cutOffValue, MyProteinList.Count - cutOffValue);
//Must cal this method to correct for the removed proteins
RebuildScansFromModifiedProteinList();
}
//Optionally returns the training sparse matrix
public static SparseMatrix BayesianScoringPSM(List <SQTScan> myScans, Parameters myParams, bool considerPresence, bool considerForms, Dictionary <int, double> peptidePriors)
{
int minNoExamplesForClassModel = 4;
PatternTools.GaussianDiscriminant.Discriminant gd = new PatternTools.GaussianDiscriminant.Discriminant();
List <sparseMatrixRow> theRows = new List <sparseMatrixRow>();
Utils.GenerateSparseMatrix(myScans, myParams, theRows, considerPresence, considerForms);
//we will just train accepting there are no outliers
List <int> unstableDims = PatternTools.GaussianDiscriminant.StabilityVerifier.Verify(theRows);
gd.MySparseMatrix.theMatrixInRows = theRows;
gd.Model(false, new List <int>(), minNoExamplesForClassModel, true, false);
if (myParams.QFilterMahalanobisDistance)
{
List <sparseMatrixRow> outlierRows = new List <sparseMatrixRow>();
//Measure the MH distance for all vectors and eliminate the ones with MH greater than specified value
foreach (sparseMatrixRow smr in gd.MySparseMatrix.theMatrixInRows)
{
double md = gd.MahalanobisDistance(smr);
if (md > myParams.QFilterMahalanobisDistanceValue)
{
outlierRows.Add(smr);
}
}
List <PatternTools.sparseMatrixRow> positiveRows = gd.MySparseMatrix.theMatrixInRows.FindAll(a => a.Lable == 1);
List <PatternTools.sparseMatrixRow> negativeRows = gd.MySparseMatrix.theMatrixInRows.FindAll(a => a.Lable == -1);
int outliersPositive = outlierRows.FindAll(a => a.Lable == 1).Count;
int outliersNegative = outlierRows.FindAll(a => a.Lable == -1).Count;
Console.WriteLine("\n===== Outlier detection with Mahalanobis Distance > {0} =====", myParams.QFilterMahalanobisDistanceValue);
Console.WriteLine("= Target class : " + outliersPositive + " / " + positiveRows.Count);
Console.WriteLine("= Labeled Decoy class : " + outliersNegative + " / " + negativeRows.Count);
Console.WriteLine("=============================================================\n");
//Make sure we have enough juice so to afford eliminating outliers
if ((negativeRows.Count - outliersNegative) > minNoExamplesForClassModel + 1)
{
//delete previous classification model
foreach (sparseMatrixRow smr in outlierRows)
{
gd.MySparseMatrix.theMatrixInRows.Remove(smr);
}
List <sparseMatrixRow> cleanedMatrix = PatternTools.ObjectCopier.Clone(gd.MySparseMatrix.theMatrixInRows);
unstableDims.AddRange(PatternTools.GaussianDiscriminant.StabilityVerifier.Verify(theRows));
unstableDims.Sort((a, b) => b.CompareTo(a));
//generate a new model based on cloned and cleaned sparse matrix
gd = new PatternTools.GaussianDiscriminant.Discriminant();
gd.MySparseMatrix.theMatrixInRows = cleanedMatrix;
gd.Model(false, new List <int>(), minNoExamplesForClassModel, true, false);
Console.WriteLine("Done cleaning outliers and generating clean model");
}
}
if (gd.ClassLableClassPackageDic.Keys.Count == 1)
{
//throw new System.ArgumentException("Not enough trainning datapoints to generate spectra / peptide classification model");
//There are no negatives! all are positives
foreach (SQTScan s in myScans)
{
//We do not provide maximum Bayesian Score so we can let other good spectra provide good examples for the protein classifier
s.BayesianScore = 1;
s.BayesianClass = 1;
}
}
else
{
gd.ClassLableClassPackageDic[-1].Prior = 0.5;
gd.ClassLableClassPackageDic[1].Prior = 0.5;
//Parallel.ForEach(thePath.MyScans, s =>
foreach (SQTScan s in myScans)
{
//The result is ordered by class number
if (gd.MySparseMatrix.theMatrixInRows[0].Values.Count < s.Bayes_InputVector.Count)
{
foreach (int i in unstableDims)
{
s.Bayes_InputVector.RemoveAt(i - 1);
}
}
if (myParams.FormsPriorForPeptides && considerForms)
{
//calculate a penalty for the negative class
gd.ClassLableClassPackageDic[-1].Prior = peptidePriors[s.NoForms];
gd.ClassLableClassPackageDic[1].Prior = 1 - peptidePriors[s.NoForms];
}
var results = gd.Classify(s.Bayes_InputVector.ToArray());
double BayesianDiference = results[0].Score - results[1].Score;
s.BayesianScore = BayesianDiference;
s.BayesianClass = 1;
if (results[0].Score < results[1].Score)
{
s.BayesianClass = -1;
}
}
//);
double BayesianMin = myScans.Min(a => a.BayesianScore);
double BayesianMax = myScans.Max(a => a.BayesianScore);
double BayesianDif = BayesianMax - BayesianMin;
foreach (SQTScan s in myScans)
{
s.BayesianScore = (s.BayesianScore - BayesianMin) / BayesianDif;
}
Console.WriteLine("Class modeled");
}
return(gd.MySparseMatrix);
}
